I have been in the credit card processing industry for 7 years. Per Visa/Mastercard rules and regulations, you have the right, and no bank can deny, that you can file for a chargeback. Don't call the credit union's actual bank location, call the number on the back of the card and dispute the charge and request a chargeback. They will transfer you to their Risk Department, ask you some questions and in most cases, issue the amount you are disputing while they investigate, on the banks dime, not the merchant's. The bank/credit union will contact their processor and request copies of the invoice/bill of sale, receipts, how the transaction was captured, etc... Once the investigation has been completed, they will come up with the conclusion. If Visa/Mastercard/Discover/Amex, whichever card was used, decides the merchant was at fault and a refund is necessary, then case closed, you got your money, if it doesnt swing in your favor, the bank will debit your account for the funds, but will notify you first to make financial arrangements.